The web cam captures a lot of planes. At night the camera is set to a longer exposure, which makes the planes leave trails. This is also happening with these purple streaks, which are just bugs that are very close to the camera, and are lit by a light close to that camera.

We know this because they look exactly like thousands of photos of "rods" - an optical phenomena cause by insects (or sometimes birds) and long exposure. You can find many examples with an image search for insect+rods

In the first two minutes of the video they describe how they film the same night time scene at 30 fps (frames per second) and again at 1000 fps. In the 30 fps the "rods" form. But at 1000 fps you can see it's just a moth.

Here I've overlaid the the purple "rods" from the new video onto an image that was known to be a moth